MODELING THE NEAR-FIELD COUPLING OF EMC FILTER COMPONENTS

1Sanaa.Zangui,

Modeling the near-field coupling of EMC filter components #Systems Simulation#TH-PM-2

MODELING THE NEAR-FIELD

COUPLING OF EMC FILTER

COMPONENTS July 29, 2010

Sanâa.ZanguiLaboratoire Ampère

Lyon, [email protected]

2

Outline• Introduction• Aims• Equivalent model• Validation• Summary• Questions

Sanaa.Zangui, Modeling the near-field coupling of EMC filter components

3

Introduction


• In Power electronic

=> noises

• Low pass filter => reduce conducted noises(HF)

Power electronic

systemFilter Motor

by conduction

by radiation

Mag

nitu

de (d

B) Low pass filter

Frequency

4

Introduction• Magnetic Coupling Analysis

(Low voltage/ high current)• Near-field Approximation. - Distance between

components<< wavelenght λ - Maximum frequency (100MHz)

=> λmax= 3meters

• Parasitic parameters and EMC Filter Performances:

- Self-parasitic - Filter components coupling.


Mag

nitu

de (d

B)

1MHz30MHz

Mutuals inductances

Frequency

The self-parasitics of components

1 2

Cy2

LDM

Cy1

EPC

EPR

LDM

Cy2

ESR2

ESL2

ESR1

Cy1

ESL1

MM 2 1

M3

5

AimsTaking into account the effects of parasitic parameters in the first step of designer a filter

• Equivalent Model Components :– Model the magnetic near-field produced by filter components– Take into account the near electromagnetic environment– Integrated in an electrical circuit software

• Compute Coupling Effects

– Using the equivalent model of components– According to their geometric placement.


6

Equivalent model(Multipolar expansion)

• 3D EM fields : multipolar expansion


• The field is computed outside the sphere that contains the equivalent source.

n=1 m=0 (dipole) n=2 m=0 (quadrupole)

7

Equivalent model (Equivalent model)

• The expression of the magnetic field :

• Qnm are functions of H• Computing H by using 3D numerical model or

measurement


n: degree, m: azimuthal order, Ynm : The spherical harmonics functions

Qnm are parameters which need to be identified => equivalent model of the radiated field component

)),(Y)1((Q41H nm2nm

nrn

8

Equivalent model (Mutual inductance)

• Using the equivalent radiated field source model.

• The spheres which contain each of the sources don’t intersect

• The expression of the mutual inductance is:


Sphere 2 Sphere 1Z21

r2 r1

r

L2 L1

H

Z

X

Y

The coefficients of the multipolar expansion of sources 1 and 2 must be expressed in the same reference => translation.

)Q*Q()1(112nmm1n,

max

10

0212

21

N

n

n

nm

m

kiijM

9

Equivalent model (Computing method)


Component 1 Component 2

H1 field by numerical modeling

or measurement

H2 field by numerical modeling

or measurement

Q1nm Computation Q2nm Computation

Equivalent model 1 Equivalent model 2

Rotation + translation in the reference1 of Q2nm => Q’2nm

Computation of the mutual inductance M in fonction of Q1nm and Q’2nm

The translation is based on the“Addition Theorem for Vector Spherical Harmonics”

10

Equivalent model (Numerical modeling)

• H field by FEM method(Flux3D®)


Infinite box

Sphere of validity

Element to modeling

Normal component of H => Qnm => equivalent model => mutual inductance

To result this case :

- Flux3D => 2000 unknows

- Multipolar expansion :

For n=Nmax=3 =>15unknows For n=Nmax=5 => 35unknows

11

Validation(case 1)

• Our result was compared to the numerical result computed by FEM(Flux3D cedrat).

• Two loops, C1 and C2 with a radius “Rspire” of 10 cm, separated by r

• At r =0.2m the error is greater for Nmax=3 than Nmax=5


0.2 0.4 0.6 0.8 10

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6 x 10-8

2*Rspire r 1 (m)

Mut

ual i

nduc

tanc

e (H

)

Nmax = 3 Nmax = 5Flux3D

0.2 0.4 0.6 0.8 10

2

4

6

8

10

12

2*Rspire r 1m

Rel

ativ

e er

ror c

ompa

red

to F

lux3

D (%

)

Nmax=3Nmax=5

X

Y

Sphere 2

Sphere 1

r

C1

C2

Z

a1

a2

Relative error (%)Mutual inductance(H)

12

Validation(case 2)

• For the same previous loops C1 and C2 • For a rotation of 45° around the y axis of the loop C2

• The results are similar to the previous case


0.2 0.4 0.6 0.8 10

0.2

0.4

0.6

0.8

1

1.2

1.4 x 10-8

2*Rspire r 1 (m)

Mut

ual i

nduc

tanc

e (H

)

Nmax = 3 Nmax = 5Flux3D

0.2 0.4 0.6 0.8 10

1

2

3

4

5

6

7

8

9

2*Rspire r 1m

Rel

ativ

e er

ror c

ompa

red

to F

lux3

D (%

)

Nmax=3Nmax=5

X

Y

Sphere 2

Sphere 1r

C1

C2

Z

a1

a2

Z2

= 45°

Mutual inductance(H)Relative error (%)

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Summary


• The method is validated :– Using multipolar expansion => equivalent model of the radiated field of

components.– Using the equivalent model to compute the coupling (Mutual inductance) between

components.• Apply this method to more complex components. • Measurement system that measures Qnm components .• Couple this method with Partial Element Equivalent Circuit

(PEEC)=> filter modeling including all coupling (track/track, components/components, components/track).

• The cylindrical harmonics can be considered for modeling components such as capacitors or cables.

• Provide component libraries including models of coupling between power electronic components.

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Questions


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MODELING THE NEAR-FIELD COUPLING OF EMC FILTER COMPONENTS